A. Technical Field
The present invention relates generally to the thermal processing of silicon wafers. More particularly, the present invention pertains to the high temperature annealing of silicon wafers.
B. Background of the Invention
The annealing of silicon wafers is conducted at relatively high temperatures. To minimize the development of surface defects during such thermal processing, silicon wafers are surrounded during annealing by a process atmosphere that does not react with solid silicon.
Nonetheless, the presence of even a minute quantity of an impurity in the process atmosphere that surrounds a silicon wafer during annealing can cause pitting to occur in the surface of the silicon wafer. The presence of pits in the surface of a silicon wafer will reduce the reliability of semiconductor devices manufactured from that wafer. Defects in the surface of a silicon wafer can, for example, dramatically degrade the integrity of any gate oxide subsequently formed over that surface defect.